server.js: rewritten to use Promises
server.js: rewritten to use Promises

storytouch/etherpad-lite,storytouch/etherpad-lite,aptivate/etherpad-lite,joequant/etherpad-lite,ether/etherpad-lite,joequant/etherpad-lite,joequant/etherpad-lite,storytouch/etherpad-lite,joequant/etherpad-lite,aptivate/etherpad-lite,aptivate/etherpad-lite,ether/etherpad-lite,aptivate/etherpad-lite,ether/etherpad-lite